EP0054571A1 - Licht-empfängerkreis - Google Patents

Licht-empfängerkreis Download PDF

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Publication number
EP0054571A1
EP0054571A1 EP81901676A EP81901676A EP0054571A1 EP 0054571 A1 EP0054571 A1 EP 0054571A1 EP 81901676 A EP81901676 A EP 81901676A EP 81901676 A EP81901676 A EP 81901676A EP 0054571 A1 EP0054571 A1 EP 0054571A1
Authority
EP
European Patent Office
Prior art keywords
voltage
output
amplifier
comparing means
control
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP81901676A
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English (en)
French (fr)
Other versions
EP0054571A4 (de
EP0054571B1 (de
Inventor
Takatoshi Minami
Hiroshi Nishimoto
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fujitsu Ltd
Original Assignee
Fujitsu Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Fujitsu Ltd filed Critical Fujitsu Ltd
Publication of EP0054571A1 publication Critical patent/EP0054571A1/de
Publication of EP0054571A4 publication Critical patent/EP0054571A4/de
Application granted granted Critical
Publication of EP0054571B1 publication Critical patent/EP0054571B1/de
Expired legal-status Critical Current

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/60—Receivers
    • H04B10/66—Non-coherent receivers, e.g. using direct detection
    • H04B10/69—Electrical arrangements in the receiver
    • H04B10/693—Arrangements for optimizing the preamplifier in the receiver
    • H04B10/6931—Automatic gain control of the preamplifier
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G3/00—Gain control in amplifiers or frequency changers
    • H03G3/20—Automatic control
    • H03G3/30—Automatic control in amplifiers having semiconductor devices
    • H03G3/3084—Automatic control in amplifiers having semiconductor devices in receivers or transmitters for electromagnetic waves other than radiowaves, e.g. lightwaves
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/60—Receivers
    • H04B10/66—Non-coherent receivers, e.g. using direct detection
    • H04B10/69—Electrical arrangements in the receiver
    • H04B10/691—Arrangements for optimizing the photodetector in the receiver
    • H04B10/6911—Photodiode bias control, e.g. for compensating temperature variations

Definitions

  • This invention relates to a light receiving circuit used for the repeaters and terminals etc. in the optical transmission system.
  • the repeaters converts the received light signal into an electrical signal and converts again it into a light signal after the waveform equalization and shaping and finally transmits it to the next repeater.
  • the received light signal is converted into an electrical signal and thereafter demodulation is carried out.
  • the automatic gain control is carried out at the repeaters and terminals so that an electrical signal of the constant level can be obtained even if the received light signal level changes.
  • Figure 1 is an ordinary light receiving circuit having the automatic gain control circuit.
  • APD avalanche photo diode
  • Figure 2 (1) to (3) show the relation between a light input level P, M of APD and a gain G of the amplifier in the methods (a) to (c) given above.
  • the solid line indicates M
  • the broken line indicates G
  • the M min is the minimum value of applicable multiplication factors of APD. When M ⁇ M min , it is not practical because the response speed of APD becomes very low due to an increase of the capacitance.
  • a signal to noise ratio (SNR) of the output signal of amplifier 13 is basically given by the following equation.
  • x is selected to a value ranging from 0.3 to 1.
  • the gain G of the amplifier is automatically determined corresponding to M O from the condition that an output of the amplifier is maintained at a constant and the. determined gain is the optimum value.
  • M which keeps an electrical signal at a constant level
  • M o the SNR is deteriorated if only an electrical signal level is kept at a constant level.
  • Figure 3 (1), (2) and (3) show such conditions. Namely, the figures show the relation between a light input and SNR corresponding to the methods (a), (b) and (c).
  • the solid line in the figure shows the ideal values, while the broken lines 32, 33, 34 respectively show the values of the methods (a), (b) and (c).
  • Said object is attained by a light receiving circuit where the amplifier output is kept at a constant by the automatic gain control of the multiplication factor of an avalanche photo diode which converts a light signal into an electrical signal and the amplifier which amplifies an output of said avalanche photo diode, thus characterized in that;
  • the 1st comparing means which compares a voltage proportional to the voltage of the multiplication factor control terminal of said avalanche photo diode and the 1st reference voltage
  • the 2nd comparating means which compares an output of said amplifier and the 2nd reference voltage
  • the 3rd comparing means which compares the 3rd reference voltage and a control voltage for automatic gain control of the amplifier
  • the high voltage generator circuit which supplies an output to the multiplication factor control terminal of said avalanche photo diode
  • the switch device which selectively changes over the.outputs of said 1st and 2nd comparators
  • an-output of said switch device is connected to the input of said voltage generator circuit
  • an output of said 2nd comparing means is connected to the control voltage input terminal for said automatic gain control, an output of said 3rd comparing means is coupled to said 1st reference voltage generator circuit, and thereby a voltage output which gives the multiplication factor which is approximated by the polygonal line to the multiplication factor of an avalanche photo diode satisfying the optimum signal to noise ratio is obtained at the multiplication factor control terminal of said avalanche photo diode, while a voltage output which makes constant the output voltage of said amplifier in accordance with said multiplication factor can be obtained at said control voltage input terminal for automatic gain control.
  • Figure 1 is the block diagram for explaining a light receiving circuit.
  • Figure 2 is the characteristic indicating the relation between the M of APD for a light input and a gain G of the amplifier in each method of the conventional light receiving circuit.
  • Figure 3 is the characteristic indicating the relation indicating the relation between a light input and SNR in each method of Fig. 2.
  • Figure 4 is the characteristic indicating the relation between a light input vs SNR, M and G in case a value of M is kept larger Than M 1 in the method (b) of the conventional light receiving circuit.
  • Figure 5 is the schematic diagram of the light receiving circuit given as an embodiment of the present invention.
  • Figure 6 is the characteristic of voltages, M and G for a light input of the circuit shown in Fig. 5.
  • Figure 7 is the characteristic indicating the relation between SNR, M and G and a light input to be controlled by the circuit shown in Fig. 5.
  • Figure 8 is the characteristic indicating the relation between V APD and M of APD.
  • Figure 9 is the characteristic indicating the relation between V AGC and G of the amplifier.
  • Figure 10 is the characteristic indicating the relation between an input-voltage V 7 and output voltage V APD of the high voltage generator circuit.
  • Figure 11 shows another embodiment of the present invention.
  • Figure 12 explains the operations in Fig. 11.
  • Figure 13 shows another embodiment of the present invention.
  • Figure 14 explains operations of Fig. 13.
  • Figure 5 is a circuit diagram of an embodiment of the present invention.
  • a light signal 11 is applied to the APD 12 and an APD output is amplified by the amplifier 13 and output to the output terminal 15.
  • An output of the amplifier 13 is divided and the connected to the level detector 14 and an output voltage V l of the level detector 14 is connected to the inverted input of the 2nd comparator consisting of a differential amplifier.
  • the 2nd reference voltage V ref2 is applied to the non-inverted input of the 2nd comparator 52.
  • An output voltage V 2 of the 2nd comparator 52 is connected to the AGC control terminal input of the amplifier 13 via the resistor 58, supplying the AGO control voltage V AGC thereto.
  • An output of the 2nd comparator 52 passes the switch device consisting of the diode 56, supplying an input voltage V 7 of the high voltage generator circuit 54.
  • An output voltage V ARD of the high voltage generator circuit 54 is input to the APD 12 and simultaneously V APD is divided into a voltage-V 6 via the resistor 56, being applied to the inverted input of the 1st comparator 51 consisting of a differential amplifier.
  • a voltage V 4 obtained by dividing the 1st reference voltage V refl is applied to the non-inverted input of the 1st comparator 51.
  • An output of the 1st comparator 51 is input to the high voltage generator circuit 54 passing the switch device consisting of the diode 55.
  • a voltage V AGC is supplied to the non-inverted input of .the 3rd comparator 53 consisting of a differential amplifier, while the 3rd reference voltage V ref3 is applied to the inverted input.
  • An output voltage V 5 of the 3rd comparator 53 determines a voltage V 4 in combination with the 1st reference voltage V refl . Then,-operations of above circuit will be explained by referring to Fig. 6.
  • a light input level is low, M is adjusted to the optimum value and the gain G of amplifier 13 is the maximum.
  • a voltage Vy rises as shown in the figure. Resultingly, an output voltage V 2 of the 2nd comparator gradually reduces.
  • a voltage V 2 is positive, it is applied to the high voltage generator circuit 54 passing the diode 56 and thereby a voltage V A p D is obtained as the output.
  • the voltage V A p D also reduces as the voltage V 2 reduces.
  • M of APD also reduces.
  • the voltage V APD reduces until the voltage V 6 divided from the voltage V APD reaches the voltage V 4 divided from the 1st reference voltage V refl .
  • P 2 ' the voltage V 6 reaches the voltage V 4 , a positive voltage is output to the output of the 1st comparator and thereby the diode 55 turns ON, forming the loop through the 1st comparator 51 and the high voltage generator circuit 54, keeping the V APD at a constant.
  • the value of M becomes a constant.
  • the voltage V 2 is positive until a light input level reaches the point P2' of Fig. 6 as shown in above and is clamped by the diode 57.
  • the voltage V AGC reduces and thereby the gain G of the amplifier 13 also reduces.
  • the 3rd reference voltage V ref3 is obtained.
  • a voltage of the cut- put voltage V 5 of the 3rd comparator 53 changes from a positive to a negative, causing the voltage V 3 to change to a negative.
  • FIG. 7 shows the optimum values of SNR, M and G for a light input with the solid lines 71, 73, 75, and also shows the approximate values obtained by the light receiving circuit of the embodiment of the present invention with the broken lines 72, 74 and 76.
  • Figure 8 shows the characteristic indicating an example of the relation between T APD and M of APD 12.
  • Figure 9 is the characteristic indicating an example of the relation between V AGC and the gain G of amplifier 13.
  • Figure 10 shows the characteristic indicating the relation between the input voltage V 7 and output voltage V APD of the high voltage generator circuit 54.
  • the multiplication factor M of APD is approximated to the optimum value M o with the polygonal line having three turning points (for the gain G, it is automatically approximated to the ideal condition), but it is also possible to obtain a modification of the embodiment which more approximates theSNR to the optimum value as indicated in Fig. 11 by additionally providing in parallel plurality of the 3rd comparators as in the case of Fig. 11 and by setting the reference voltage corresponding to the 3rd reference voltage to the other value.
  • the comparators 53-1, 53-2 to 53-n are provided in parallel to the comparator 53, and thereby the reference voltages V ref4 , V ref5 to V refn are input to the inverted inputs while the V AGC is input to the no-inverted inputs.
  • the outputs of the comparators 53-1 to 53-n are connected with the resistors R 4 , R 5 to R n , diodes D 4 to D n , D 4-1 to D n-1 .
  • the voltages V ref3 , V ref4 , V ref5 to V refn are in the following relation as Vref3 > V ref4 > V rev5 ⁇ >V refn, while the resistors R 3 , R 4 , R 5 to R n are in the relation as R 3 > R 4 > R 5 - > R n .
  • the steps up to saturation of the output voltage of the comparator 53 is the same as that of the circuit shown in Fig. 5.
  • an output voltage V 5-1 of the comparator 53-1 becomes negative and thereby the voltage V 4 is also lowered.
  • Figure 13 shows another embodiment of the present invention.
  • the circuit indicated has the same functions as those of the circuit shown in Fig. 5, Only difference from the circuit of Fig. 5 is that the comparator 52, diode 55 and resistor 59 are removed, and an output of the high voltage generator circuit 54 is connected to the resistor R 2 which is connected to the reference power supply V refl via the diode D 1 .
  • the present invention provides a light receiving circuit with a simple structure which can assure wide light input dynamic range without allowing the SNR to be deviated largely from the optimum value and the desired variable gain width of amplifier to be widened.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Optical Communication System (AREA)
  • Light Receiving Elements (AREA)
EP81901676A 1980-06-25 1981-06-15 Licht-empfängerkreis Expired EP0054571B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP55085246A JPS5911215B2 (ja) 1980-06-25 1980-06-25 光受信回路
JP85246/80 1980-06-25

Publications (3)

Publication Number Publication Date
EP0054571A1 true EP0054571A1 (de) 1982-06-30
EP0054571A4 EP0054571A4 (de) 1982-11-25
EP0054571B1 EP0054571B1 (de) 1985-05-08

Family

ID=13853203

Family Applications (1)

Application Number Title Priority Date Filing Date
EP81901676A Expired EP0054571B1 (de) 1980-06-25 1981-06-15 Licht-empfängerkreis

Country Status (6)

Country Link
US (1) US4495410A (de)
EP (1) EP0054571B1 (de)
JP (1) JPS5911215B2 (de)
KR (1) KR840002284B1 (de)
DE (1) DE3170387D1 (de)
WO (1) WO1982000073A1 (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0282801A1 (de) * 1987-03-17 1988-09-21 Siemens Aktiengesellschaft Regelung des Multiplikationsfaktors von Lawinenphotodioden in optischen Empfängern
EP0313914A1 (de) * 1987-10-26 1989-05-03 Siemens Aktiengesellschaft Schaltungsanordnung mit einem an einen opto-elektrischen Wandler angeschlossenen Vorverstärker

Families Citing this family (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60146539A (ja) * 1984-01-10 1985-08-02 Nec Corp 光受信器
US4688268A (en) * 1984-01-11 1987-08-18 Chevron Research Company Fiber optic receiver having a combined baseline clamp and automatic gain control detector
US4679252A (en) * 1984-01-11 1987-07-07 Chevron Research Company Fiber optic receiver having a method and an apparatus for data clock extraction
JPS61177832A (ja) * 1985-02-04 1986-08-09 Nippon Telegr & Teleph Corp <Ntt> 光受信装置の自動利得制御方式
JPS6313534A (ja) * 1986-07-05 1988-01-20 Nec Corp バイアス電圧制御回路
JPS6450112A (en) * 1987-08-20 1989-02-27 Nec Corp Dc/dc converting circuit
JPH01186168A (ja) * 1988-01-20 1989-07-25 Oki Electric Ind Co Ltd 受光用高圧発生回路
JPH02113640A (ja) * 1988-10-21 1990-04-25 Toshiba Corp 自動利得制御装置
JPH02209029A (ja) * 1989-02-09 1990-08-20 Toshiba Corp 自動利得制御装置
JP2713224B2 (ja) * 1995-05-01 1998-02-16 日本電気株式会社 光受信器
US5929982A (en) * 1997-02-04 1999-07-27 Tektronix, Inc. Active APD gain control for an optical receiver
US6188059B1 (en) 1998-01-30 2001-02-13 Sumitomo Electric Industries, Ltd. Photocurrent monitor circuit and optical receiver
US6313459B1 (en) 2000-05-31 2001-11-06 Nortel Networks Limited Method for calibrating and operating an uncooled avalanche photodiode optical receiver
US20050224697A1 (en) * 2004-04-08 2005-10-13 Naoki Nishiyama Light-receiving circuit capable of expanding a dynamic range of an optical input
WO2006018941A1 (ja) * 2004-08-18 2006-02-23 Rohm Co., Ltd 判別回路、ゲイン調整回路、信号処理回路、及び電気機器
US9780743B2 (en) * 2015-10-22 2017-10-03 Google Inc. Light sensor readout system and method of converting light into electrical signals

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5358748A (en) * 1976-11-08 1978-05-26 Hitachi Ltd Light receiving amplifier
JPS5359345A (en) * 1976-09-21 1978-05-29 Post Office Signal level stabilizer
JPS5390802A (en) * 1977-01-21 1978-08-10 Hitachi Ltd Control system for light receiving system

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4236069A (en) * 1978-10-16 1980-11-25 Varo, Inc. Avalanche photodiode gain control system
US4399416A (en) * 1980-11-10 1983-08-16 Texaco Development Corporation Floating point amplifier

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5359345A (en) * 1976-09-21 1978-05-29 Post Office Signal level stabilizer
JPS5358748A (en) * 1976-11-08 1978-05-26 Hitachi Ltd Light receiving amplifier
JPS5390802A (en) * 1977-01-21 1978-08-10 Hitachi Ltd Control system for light receiving system

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of WO8200073A1 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0282801A1 (de) * 1987-03-17 1988-09-21 Siemens Aktiengesellschaft Regelung des Multiplikationsfaktors von Lawinenphotodioden in optischen Empfängern
AU600804B2 (en) * 1987-03-17 1990-08-23 Siemens Aktiengesellschaft Method of and apparatus for the regulation of the multiplication factor of avalanche photo-diodes in optical receivers
EP0313914A1 (de) * 1987-10-26 1989-05-03 Siemens Aktiengesellschaft Schaltungsanordnung mit einem an einen opto-elektrischen Wandler angeschlossenen Vorverstärker
AU608376B2 (en) * 1987-10-26 1991-03-28 Siemens Aktiengesellschaft Circuit arrangement with a preamplifier connected to an opto-electric transducer

Also Published As

Publication number Publication date
KR830007003A (ko) 1983-10-12
EP0054571A4 (de) 1982-11-25
JPS5911215B2 (ja) 1984-03-14
DE3170387D1 (en) 1985-06-13
WO1982000073A1 (en) 1982-01-07
EP0054571B1 (de) 1985-05-08
US4495410A (en) 1985-01-22
KR840002284B1 (ko) 1984-12-14
JPS5711548A (en) 1982-01-21

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